In theory, eco-industrial parks can make significant improvements in the environment. In that light, this article analyses six planning methods currently in use in the Netherlands. The most salient findings are that these methods lack an explicit vision of sustainability, they do not give due consideration to symbiotic or utility-sharing options, they do not sufficiently engage the companies involved in the development and their policy instruments have a limited environmental impact. The planning methods prove to have many shortcomings: the definition of sustainability is unclear; there are no quantitative standards; information on symbiosis and utility sharing is inadequate; the economic and organizational implications are largely ignored and the environmental impact is insufficiently monitored. However, eco-industrial parks can only have greater environmental benefits through symbiosis and utility sharing. Therefore, location- and company-specific factors have to be taken into consideration. Copyright © 2003 John Wiley & Sons, Ltd. and ERP Environment